DESCRIPTION: MMP-2 is a member of the family of matrix metalloproteinases (MMPs), which together cleave a broad range of tissue components. While this property of the MMPs is a beneficial feature of normal development and tissue adaptation, uncontrolled MMP-2 activity has been strongly associated with inflammatory diseases, such as periodontal disease and arthritis, and tumor expansion and metastasis. This application is designed to develop compounds, which specifically inhibit MMP-2 activity. Since cleavage of molecules by MMP-2 occurs only if there is binding between the enzyme and substrate molecules, the specific mechanism by which MMP-2 binds its main collagen substrates will be investigated. In a collaborative effort, molecular biology and protein structural analysis methods will be applied to first identify specific MMP-2 binding sites on collagen by screening a random peptide library and mapping the functional peptide sequences on collagen. To identify the precise collagen binding site residues on MMP-2, nuclear magnetic resonance studies will be used to analyze the MMP-2 collagen binding domain (CBD) complexed with synthetic peptides, which mimic the CBD binding sites on collagen. The specificity of the identified sites and amino acids will be tested in competitive ligand binding assays and by analyzing the effects of site-specific mutations in the CBD. Once the precise binding sites on both collagen and MMP-2 are defined, small molecules will be developed that can inhibit the full-length native MMP-2 activity by competing for substrate binding and by substituting binding site residues on the CBD. This will be accomplished in both MMP-2 ligand binding and activity assays, and in experiments with MMP-2 expressing cells. The proposed studies should define the specific binding site interactions between MMP-2 and its main collagen substrate and explore a new strategy to inhibit MMP-2 in inflammatory diseases and cancer based on competition for substrate binding.